Can Harlequin Rasbora live with Zebra Danio?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Harlequin Rasbora and Zebra Danio Don't Make an Easy Pair
They can coexist, but you need to manage the setup carefully. The temperature margin is tight — only 2°F of safe overlap, which leaves little room for thermostat drift.
Harlequin Rasbora
Trigonostigma heteromorpha
| Adult Size: | 2.0" |
| Temperament: | peaceful |
| Min Tank: | 10 gal |
| Temperature: | 73-79°F |
| pH Range: | 5.5-7.0 |
Zebra Danio
Danio rerio
| Adult Size: | 2.0" |
| Temperament: | peaceful |
| Min Tank: | 10 gal |
| Temperature: | 64-75°F |
| pH Range: | 6.5-7.5 |
Water Parameter Overlap
| Parameter | Harlequin Rasbora | Zebra Danio | Overlap |
|---|---|---|---|
| Temperature | 73-79°F | 64-75°F | 2°F ✓ |
| pH | 5.5-7.0 | 6.5-7.5 | 0.5 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + peaceful. Both peaceful → minimal conflict.
Score: 60.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 10 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 73°F and 75°F.
- pH: maintain 6.5 – 7.0.
- Hiding spots: essential for Harlequin Rasbora — caves, plants, or driftwood to retreat when feeling stressed.
- Water changes: 25% weekly minimum. Two species mean double the bioload.
🔧 Tank Stocking Calculator
Enter tank size to calculate safe stocking levels:
Recommended Equipment
Based on tank size 10+ gallons:
Plant supplement for planted tanks
Explore Related Checks
See what else works with these fish:
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Harlequin Rasbora may act differently from its species average. Always observe, quarantine new arrivals for 2-4 weeks, and avoid overcrowding. If a pairing says CAUTION, start with a smaller group and a lid.